1. Field of the Invention
The present invention relates to a linear guide apparatus including a guide rail and a slider movable on the guide rail through rolling of balls interposed therebetween, and in particular, to a linear guide apparatus having an improved ball retainer.
2. Description of the Prior Art
A prior art ball retainer of a linear guide apparatus of this type is disclosed, for example, in U.S. Pat. No. 4,253,709 (Japanese Patent Laid-Open Publication No. 55-72912).
As shown in FIGS. 10 and 11, the ball retainer 3 of a linear guide apparatus including a guide rail 1 and a slider 2 movably mounted on the guide rail 1 through rolling balls B is made of a thin steel plate. The ball retainer 3 is formed by stamping so that both sides have a wave form along the inner surface of the slider 2. In each of the sides of the wave form, a window 5 is formed having a width somewhat smaller than a diameter of the ball B and extending axially along the length of the ball retainer 3.
The retainer 3 is secured to the inner surface of the slider 2 by fixing screws 4, and the balls B mounted in the window 5 are held in ball rolling grooves 6 and 7 of the inner surface of the slider 2.
When the slider 2 is linearly moved on the guide rail 1, many balls B roll in the ball rolling grooves 6 and 7 and in the ball rolling grooves 8 and 9 of both side surfaces of the guide rail 1.
However, in such a prior art linear guide apparatus, the ball retainer 3 is made of a thin steel plate, and the balls B are held in the ball rolling grooves 6 and 7 by ball holding stocks of the windows 5 formed in the sides of the ball retainer 3. As a result, the following problems are encountered.
In the prior art apparatus, since a lubricant is not supplied through the ball retainer portion, lubrication is apt to be interrupted.
It is necessary to remove the ball retainer 3 at the time of mounting the balls B in the ball rolling grooves 6 and 7 of the slider and at the time of replacing the balls B. Thus, the work is troublesome. Furthermore, since the ball retainer is tightened by screws to the slider, the assembling is also troublesome.